Tasmania's biggest salmon producer announces a record profit and spruiks its "excellent environmental credentials and compliance" as it tows fish pens into place to begin its controversial east coast expansion.

Victoria's ambitious renewable energy targets of 40 per cent by 2025 will be cemented in law, with legislation introduced to State Parliament to protect their future, as the Government announces two new solar farms to power the state's tram network.

The koala population in Campbelltown is the largest and healthiest in the Sydney basin, but locals fear urban development and the risk of chlamydia infection are putting their native neighbours at risk.

One of Australia's leading water scientists says the contamination from millions of litres of highly toxic water is "internationally significant", with heavy metals in the Wingecarribee River far exceeding safe environmental levels.